The present invention refers to an optically-connected system, in particular through optical rays with infrared frequency, for exchanging data among industrial automation devices.
Currently, in industrial automation applications, it is common to realize a plurality of connection elements (that contain input and output lines towards external devices such as sensors, etc.) placed one beside the other (for example on a DIN-type bar) and mutually connected and connected to a data collecting and ordering element (commonly known as “power terminal”), which, in turn, through a field bus, sends data, collected from different external devices, to an upstream numeric control. In order to realize the data exchange between connection elements and data collecting and ordering element, a serial connection is commonly provided that allows both the passage of different data, and the supply of various elements. The connection and data collecting and ordering elements are each contained inside a respective box, having various shapes and sizes, adapted to be assembled on bars or operatively installed in another way.
A system built in this way has many problems: first of all, when one of the connection elements fails, in some cases it is necessary to disassemble the whole row of elements, since such element cannot be individually removed; in other cases, if it is possible to remove the element shaped as a card from the box that contains it, its removal stops the serial connection line and therefore, if one has not a connection element to immediately replace it, such line is interrupted and then deactivated, with obvious disadvantages.
Moreover, the boxes containing the various elements are very often of a complicated configuration and therefore are of a very high cost for stamping them. Where the boxes are simpler as configuration, they are lacking many functionalities that current automations require.
Other problems of the above system are the presence of “physical” contacts that the various elements have in order to be mutually connected: such contacts are subjected to wear, dirt and other environmental conditions, such as for example electromagnetic disturbances, that damage their functionality, in turn damaging the other system connection elements.
Still more, the supply that it is possible to provide through the serial connection is relatively limited, allowing to mutually connect a maximum number of elements that is equal to 8 or 16 digital outputs each one at 250 mA. If the necessary connection elements are greater than this number, it is necessary to provide for a further system, serially connected to the previous one, with obvious problems of cost and connections.
Object of the present invention is solving the above prior-art problems by providing an optically-connected system that is simple to be realized, install, use and subject to maintenance, is of a reduced cost from the points of view both of manufacturing, and of use, and above all is much more efficient and reliable with respect to connections currently present on the market.
Another object of the present invention is providing an optically-connected system that allows quickly replacing faulty or unusable elements, that can moreover do without some elements in the series without anyway compromising the data exchange capability among the elements being present, and that is insensitive to electromagnetic disturbances on the lines, that are a frequent cause of errors in current connections. With an arrangement of this type, it is possible to group the various elements composing the series by families of use, simplifying and increasing the safety for maintenance people involved.
A further object of the present invention is providing an optically-connected system as mentioned above that is scarcely sensitive to influences from the surrounding environment, such as for example dirt, noises, vibrations, etc.
The above and other objects and advantages of the invention, as will appear from the following description, are obtained by an optically-connected system as claimed in claims 1 and 2. Preferred embodiments and non-trivial variations of the present invention are claimed in the dependent claims.